Inertia responsive carburetor fuel flow control means

ABSTRACT

AN INERTIA RESPONSIVE CARBURETOR FUEL FLOW CONTROL MEANS WHICH ACCOMMODATES FOR VARIATIONS IN FUEL LEVELS IN THE FUEL BOWL CAUSED PRIMARILY BY CENTRIFUGAL FORCES SET UP BY VEHICLE CORNERING. THE INVENTION IS USED WITH MULTI-BARREL CARBURETORS HAVING SEPARATE PASSAGES TO EACH BARREL FROM THE FUEL BOWL. AN INERTIA SENSING MEANS, EITHER IN THE FORM OF A SPRING BIASED WEIGHTED ARM OR A FUEL SURFACE ANGLE SENSOR, CONTROLS THE POSITIONS OF METERING RODS THAT COOPERATE WITH ORIFICES IN EACH PASSAGE TO MAINTAIN ESSENTIALLY IDENTICAL RATES OF FLOW THROUGH EACH PASSAGE WHEN THE PASSAGES EXPERIENCE DIFFERENT FUEL HEADS.

Mal'Ch 6, 1973 R. s. HARRISON ET AL INERTIA RESPONSLVE CARBURETOR FAUELFLOW CONTROL MEANS Filed Nov. 1l, 1971 United States Patent O 3,719,352INERTIA RESPONSIVE CARBURETOR FUEL FLOW CONTROL MEANS Robert S.Harrison, Detroit, and Thomas R. Johnson, Ann Arbor, Mich., assignors toFord Motor Company, Dearborn, Mich.

Filed Nov. 11, 1971, Ser. No. 197,901 Int. Cl. F02m 5/02 U.S. Cl. 261-23A 11 Claims ABSTRACT F THE DISCLOSURE An inertia responsive carburetorfuel flow control means which accommodates for variations in fuel levelsin the fuel bowl caused primarily by centrifugal forces set up byvehicle cornering. The invention is used with multi-barrel carburetorshaving separate passages to each barrel from the fuel bowl. An inertiasensing means, either in the form of a spring biased weighted arm or afuel surface angle sensor, controls the positions of metering rods thatcooperate with orices in each passage to maintain essentially identicalrates of flow through each passage when the passages experiencedifferent fuel heads.

BACKGROUND AND SUMMARY OF THE INVENTION Most multi-barrel carburetors inuse today have laterally spaced main jets and main fuel wells whichinterconnect the fuel bowl and the several venturis. The result is thatwhen the vehicle corners the centrifugal forces acting on the fuel inthe carburetor fuel bowl cause the fuel surface to assume an anglerelative to the normal horizontal fuel level. If the jets and the mainwells are located symmetrically on either side of the fuel bowl centerline, one of the jets and main wells experiences an incerased fuel headwhile the other of the jets experiences a decreased head. Thus, themixture delivered by one of the venturi barrels is overly rich while themixture delivered by the other barrel is overly lean. In a typical V8engine, one of the barrels of a two-barrel carburetor feeds the rightbank of cylinders, while the second barrel feeds the left bank. If thecornering forces are exceptionally large, the engine may experiencestumble because of improper fuel mixtures.

This invention provides a fuel flow control means that eliminatesstumble during severe cornering maneuvers. The invention also providesmeans that control fuel ows to each barrel to accommodate for thedifferent fuel heads acting on the individual main jets and main fuelwells. The invention further provides means that deliver essentiallyidentical fuel ows through each of the main jets regardless of whetherthe vehicle is proceeding in a straight direction or it is cornering.Finally, the invention provides fuel flow control means that isadaptable for use with conventional carburetors, that may beeconomically produced and that is reliable in operation.

A fuel flow control means for a carburetor having at least two barrelsconstructed in accordance with this invention includes first and secondpassage means leading from the fuel bowl to first and second barrels,respectively. First and second metering means are constructed toregulate the ows through the first and second passages, respectively. Aninertia sensor, movable in response to inertia forces acting on thecarburetor and to maintain essentially identical fuel ow rates throughthe passages irrespective of inertia forces acting on the carburetor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a cross sectional view of acarburetor taken through its fuel bowl in the longitudinal direction ofthe vehicle.

FIG. 2 is a cross sectional view taken along the line 2 2 of FIG. l.

FIG. 3 is a cross sectional view similar to FIG. 1 but showing analternate embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. l and 2 of thedrawings illustrate the invention embodied in a typical two-barrelcarburetor which is generally used as a part of a V-S engine. Thecarburetor includes a housing 12 having two barrels 14 and 16 and a fuelbowl 18 formed therein. Each of the barrels includes a substantiallyidentical main venturi 20` and booster venturi 22.

The normal operation of the carburetor is typical to that ofconventional two-barrel carburetor. Air passing through the venturis 20and 22 cause reduced air pressures at nozzles 24 relative to theatmospheric air pressure within the fuel bowl 18. The air pressuredifferential forces fuel fromy the fuel bowl through main metering jets26 and 28 into passages 30l and 32 which discharge into the respectivemain fuel wells 34. FIG. 2 is a cross sectional view through barrel 16and main jet 28y of PIG. l. A cross sectional view through venturi 14and main jets 26 would be essentially identical and would show thesecond of main wells 34 and its connecting passages. A small quantity ofair is introduced into the main wells through passages 42 -which open tothe atmosphere. The mixtures then proceed from the main wells 34 to thenozzles 24 of the booster venturis 22 through passages 38. There themixtures are introduced into the air streams passing through each barreland are discharged past the respective throttle plates 40.

The fuel bowl 18 includes a oat 42 which operates an inlet valve (notshown) to maintain a constant fuel level within the bowl. The surface ofthe fuel is designated by reference numeral 44. An inertia sensorassembly 46 is positioned on a pin 48 protruding from a wall of the fuelbowl 18 at a location between and above the main jets 26 and 28. The pinpivotally supports arm member 50 which, in turn, supports a pair oftapered metering rods 52 and 54 within each of the main jets. Themetering rods are calibrated so that when the arm member is horizontaland the fuel surface is level, the tapered portions of the rods arepartially received within the orifices of the metering jets 26 and 28.The arm member is generally U-shaped and has a pair of floats 56 and 58'positioned at each end. The vertical location of the oats is determinedin accordance with the normal fuel level 44 within the bowl 18.

When the automobile is traveling in the direction of arrow 60 along astraight path, there are no inertia forces acting upon the fuel Withinthe bowl 18. When the vehicle corners even though the speed is keptconstant, the centrifugal forces set up by the cornering cause the fuelsurface to assume an angle similar to that shown by the dotted line 62in 'FIG. 1. The magnitude of the fuel surface angle is proportional tothe centrifugal force which, in turn, is a function of the velocity ofthe vehicle and its turning radius. The floats 56 and 58 follow thesurface of the fuel and cause arm 50 to pivot about pin 48. Metering rod54 is drawn upwardly from its position in FIG. l and increases therestrictions of main jet 2-8. Metering rod 52 is lowered and decreasesthe restrictions of main jet 26. It may be seen from FIG. 1 that undercornering conditions, the fuel head acting on main jet 28 is less thanthe fuel head acting on main jet 26. Similarly, the fuel heads acting oneach of the main wells 34 are unlike. If the main jet orifices were tohave identical effective openings during cornering the fuel flow throughthe jet 28 would exceed the fuel fiow through the jet 26 because of thefuel head differential. At extreme conditions, engine stumble wouldresult either from one of the bank of cylinders having too lean amixture or the other bank of cylinders having a too rich a mixture.

It thus may be seen that the invention provides for the increasedrestriction of the effective orice of the main jet that experiences thegreater fuel head and the corresponding decreased restriction of theeffective orifice of the main jet having the lesser fuel head. The mainjets 26 and 28 and the portions of the metering rods 52 and 54interacting with the main jets are so contoured and calibrated that thefuel air ratio is kept constant for each of the barrels of thecarburetor and, consequently, for each of the banks of the V-8 engine.It has also been shown that the fuel and the pivotable float assembly 46operates as an inertia sensor to position the metering rods within theircorresponding orifices.

DESCRIPTION OF AN ALTERNATE EMBODIMENT OF THE INVENTION FIG. 3 of thedrawing illustrates an alternate embodiment of the invention. With theexception of the appara tus to be discussed below, the carburetorstructure of the second embodiment is identical to that of the preferredembodiment and the same reference numerals are used to identifyidentical parts.

The inertia sensor assembly 64 includes an inverted cross-shaped armmember 66 pivotally attached Within the fuel bowl 18 to pin 48. The armmember is normally biased into a vertically aligned position, as shownin FIG. 3 by a spring 68 which is secured to the base of the fuel bowlbetween the main jets 26 and 28. A pair of tapered metering rods 70 and72 pivotally depend from the horizontal arm 74 of the cross member 66and have tapered ends which are received within the orifices of themetering jets 26 and 28. A vertical leg 76 extends upwardly past thenormal fuel level 44 and has mounted at its end a weight 78. When thevehicle is traveling in a straightforward direction there are no forcestending to move the sensor assembly 64 out of its normal verticallybiased position. When the vehicle corners, the weight 78 is drawn bycentrifugal force to the side corresponding to the increased fuel head.As the arm pivots about the axis of pin 48 it increases the restrictionof the main jet having the greater fuel head and decreases therestriction of the main jet having the lower fuel head. The weight 78and the metering rods 70 and 72 are calibrated as a function of the fuelhead differential to maintain essentially identical flows through themain jets during vehicle cornering.

lModifications and alterations may occur to those skilled in the artwhich are included Within the scope of the following claims.

We claim: 1. A fuel flow control means for a carburetor having at leasttwo barrels and a fuel bowl comprising:

first and second passages leading respectively from said fuel bowl tosaid first and second barrels, first and second metering meansconstructed to regulate and vary the iiows through said first and secondpassages, respectively, inertia sensor means responsive to inertiaforces experienced by the carburetor,

said inertia sensor means being coupled with said first and secondmetering means to simultaneously increase the restriction of one of saidpassages and decrease the restriction of the other of said passages inresponse to inertia forces acting on said carburetor and to maintainessentially identical fuel iiow rates through said passages irrespectiveof inertia forces acting on said carburetor.

2. A fuel flow control means according to claim 1, said first and secondmetering means comprising:

a pair of metering rods,

a pair of metering orifices with said first and second passagesreceiving said metering rods.

3. A fuel tiow control means according to claim 2, said metering rodshaving tapered ends cooperating with said metering orifices.

4. A fuel flow control means according to claim 1, said inertia sensorcomprising float means pivotally mounted relative to said fuel bowlmovable in response to changes in the surface angle of the fuel withinsaid fuel bowl.

5. A fuel flow control means according to claim 1,

said inertia sensor comprising an arm pivotally mounted relative to saidfuel bowl,

an inertia weight mounted on an end of said arm,

said arm movable in response to inertia forces acting on saidcarburetor.

6. A fuel flow control means for a motor vehicle engine carburetorhaving at least two barrels and a fuel bowl comprising:

first and second passage means leading from said fuel bowl to said firstand second barrels, respectively, first and second metering orificespositioned within said first and second passages, respectively,

said orifices being laterally spaced one on each side of a line parallelto the straightforward direction of travel of the vehicle,

first and second metering rods received within said first and secondmetering orifices, respectively, and movable relative thereto toregulate flow through said orifices,

inertia sensor means responsive to centrifugal forces experienced by thecarburetor,

said sensor including an arm member pivotable about a fixed axisparallel to the straightforward direction of travel of the vehicle, saidmetering rods being carried by said arm member, said sensor means andsaid metering rods being movable in response to inertia forces acting onthe carburetor to simultaneously increase the effective restriction ofone of said passages and decrease the effective restriction of the otherof said passages and to maintain substantially identical fuel flow ratesthrough said pasages irrespective of inertia forces acting on saidcarburetor. 7. A fuel tiow control means according to claim 6, saidmetering rods having tapered ends cooperating with said meteringorifices.

8. A fuel iiow control means according to claim 6, said inertia sensormeans comprising oat means secured to said arm member at a positioncorresponding to normal height of the fuel with said fuel bowl,

said arm member being pivotally movable in response to changes in thesurface angle of the fuel within the fuel bowl.

9. A fuel flow control means according to claim 8,

said arm member having one portion extending laterally and upwardly fromits xed pivot axis and a second portion extending laterally to the otherside and upwardly from said fixed pivot axis,

said float means comprising individual dioats secured to ends of saidfirst and second portions of said arm member.

10. A fuel flow control means according to claim 6, said inertia sensormeans comprising a weight secured to said arm member at a position abovethe normal fuel level within the fuel bowl.

11. A fuel ow control means according to claim 10, spring means biasingsaid arm member toward a normal vertical position.

References Cited UNITED STATES PATENTS '2,718,387 '9/1955 'Carlson etal. 261-DIG. 50 3,633,610 1/1972 Hellqvist 137-398 6 FOREIGN PATENTS466,335 5/1937 Great Britain ..-137-38 ROBERT G. NILSON, PrimaryExaminer 5 E. K. LOOK, Assistant Examiner U.S. Cl. X.R.

261-67, 70, DIG. 50; 137-44, 45

